Mold for casting thin-walled receptacles



Feb. 23, 1943. F. JQMQRAVEcKY 2,311,680

MOLD FOR CASTING THIN WALLED REGEPTACLES 1o 10 13 13 v a INVENTORJ BYhi1 ATTORNE 1Q Feb. 23, 1943. F. J. MORAVECKY 2,311,680

' MOLD FOR CASTING THIN-WALLED RECE?TACLES Filed April 3, 1942 2Sheets-Sheet 2 INVENTOR BY W fi' fl 44/, ATTORAZEK! Patented Feb. 23,1943 MOLD FOR CASTING THIN -WALLED RECEPTACLES Frank J. Moravecky,Beaver Falls, Pa. Application April 3, 1942, Serial No. 437,470

4 Claims.

This invention relates to the making of castings from molten metal,particularly iron. It is among the objects of the invention to permit aconsiderable saving in metal used in casting by providing a mold inwhich an exceptionally light, thin-Walled casting can be cast, whichnevertheless has the strength of heavier castings.

The difficulty heretofore experienced in casting thin-walled articleshas been due entirely to the fact that, since an exceptionally thin moldcavity was required, the molten metal poured therein chilled rapidly andsolidified, thereby choking the cavity and prohibiting a completefilling thereof.

To the best of my knowledge in cast iron sanitary ware, such as sinks ortubs, the present limit of thinness, when the iron is poured at theusual casting temperature (approximately 2500 F.), is inch. It is, ofcourse, true that such a limit is a function of the size and shape ofthe final casting as well as the ladle temperature of the iron. Largerbath or wash tubs require a larger mold cavity and therefore the metalmust fill a greater area. Consequently, their limit of thinness isgreater than that of the sink, and is, in so far as I have determined,inch. Thus, I do not intend to limit my invention to castings having awall thickness of less than A; inch, and any casting which, except forthe practice of my invention, would have solidified prematurely withinthe mold cavity is within the scope of my invention.

The mold provided according to this invention has a normal or main wallcavity of flow-limiting thinness, by which I mean of such thinness thatmolten metal supplied to the cavity will solidify in it before fillingthe cavity, thereby resulting in a defective or incomplete casting.Wholly to fill the entire main wall cavity without increasing itsthickness, the cavity is interrupted throughout its entire extent byvertically disposed channels of free-flow depth, by which I mean of suchdepth that molten metal will flow from the pouring sprues through thechannels and thence to the parts of the main wall cavity furthestremoved from the sprues. These channels are spaced from each other atintervals of not more than twice the distance that the metal will flowthrough the main wall cavity. Thus, metal which flows upwardly througheach adjacent pair of channels will spread out lat-' erally from themthroughout the entire main Wall cavity space between them.

The invention is illustrated in the accompanying drawings in which Fig.1 is a plan view of a cope pattern used to form the cope portion of themold; Fig. 2 a vertical section through the cope pattern and its flask;Fig. 3 a vertical section through a cope flask tamped with sand andstripped from the cope pattern; Fig. 4 a view similar to Fig. 2 of adrag pattern and its flask; and Fig. 5 a section through the cope anddrag flasks closed and ready to receive the molten metal.

Referring in detail to the above drawings, the mold used for the castingoperation comprises the usual two mold sections, namely, cope I, and adrag 2, which, when closed upon each other leave a mold cavity 3therebetween.- For illustrating the invention the mold cavity 3 isshaped to form a sink and the invention will be described with referenceto such ware. The manner of forming the cope and drag is well known tothe art and requires only brief description. In order to form the cope,a cope flask 4 is placed over a cope pattern 5 and sand 5 is manually ormechanically tamped into the flask and about the pattern. The flaskcontaining the imprinted sand is then separated from the pattern. Thedrag is formed in an identical manner by a drag flask 1 and pattern 8.After separating the drag flask and pattern the flask is inverted andaccurately aligned with the cope flask to form the completed mold.

The cope pattern, as seen in Fig. 2, comprises a base 9, having ahorizontal surface Hi to support the flask 4, sprue gate patterns I I,feed gate patterns l2, and the pattern to imprint the sand with theshape of the final casting comprising a ledge-forming element [3,vertically inclined side walls I4, and wall l5 slightly inclined fromthe horizontal to form the bottom of the sink. The center of the wall I5is provided with a circular knob IE to form the drain of the casting.The cope flask comprises side walls l1 which are flanged at either end.Thus when the flask is placed over the pattern and sand 6 tamped thereina cope is provided which has sprue gates l8, feed gates l9, and thereverse imprint of the casting pattern.

The drag flask and pattern should be clearly understandable from Fig. 4without detailed verbal description. The drag pattern, of course, mustbe accurately fashioned with respect to the cope pattern so that theproper mold cavity will be left between the cope and drag when they areclosed. Both the cope and the drag flasks may be provided with ribs 20in order to more firmly support the sand therein. These flasks also areprovided with aligned apertures to receive guide metal supplied theretosolidifies before completely.

filling the mold. In a mold for a sink or a tub such a thickness couldbe as low as /3 inch and normally would not exceed s? of an inch. In

order to permit molten metal to completely fill the cavity thecasting-forming portion of the cope is provided with Channels 2| whichshould have a depth of about inch.

In order to form the channels in the cope the cope pattern must beprovided with ribs 22. The

arrangement of the ribs in the pattern must be predetermined with regardto the size of the casting to be made. Thus, the channels formed by theribs must be placed closely enough together so that the metal will notsolidify while spreading from the channels into the thinner cavitybetween them. Such determination should be made for each casting but, byway of example, a spacing of six inches between channels is sufficientfor larger ware such as tubs, while in casting smaller tubs or sinks thespacing could be eight inches with a maximum of about ten inches. Sincethere are variables in metals, wall thicknesses, and other castingconditions it should be understood that the above spacings areapproximations and not definite limitations.

A particular arrangement for the ribs is shown in Fig. 1 in which theoutside surface of the wall l5 of the cope pattern is provided withparallel longitudinal ribs which are intersected by parallel horizontalribs both of which being continued along the vertically inclined sidewalls Id of the cope pattern. The intersecting ribs on wall 15 of thepattern imprints the cope with a plurality of squares bounded bychannels so that, when the poured metal solidifies and chokes anyfurther flow through the thin mold cavity, subsequent molten metal canflow in the path afforded by the channels and spread into the unfilledsquares between them from any one or all of the channels forming thesquares. The ribs on the vertical side wall M of the pattern imprintchannels in the cope which facilitate and speed the rising of the metalin the mold cavity as well as providing pathways for molten metal tospread beyond any metal which may have solidified in the narrow cavity.It should be understood that this particular arrangement is merelypreferred and that other arrangements which suit the purposes of theinvention ar within its scope.

As should be apparent from the above description the receptacle formedby this mold is a casting having a normal wall thickness as low as inchand having ribs on its outside surface which locally increase the wallthickness to approximately inch. These ribs reinforce the casting sothat it has sufficient strength to withstand the service conditions towhich a heavier casting of /4 inch thickness throughout is normallysubjected. In addition the casting uses considerably less metal than theheavier /4 inch casting and is therefore much lighter and moreeconomical.

According to the provisions of the patent statutes, I have explained theprinciple and method of practicing my invention and have illustrated anddescribed what I now consider to represent its best embodiment. However,I desire to have it understood that, within the scope of the appandedclaims, the invention may be practiced otherwise than as specificallyillustrated and described.

Iclaim:

1. A mold for casting a thin wall receptacle or like structure frommolten metal, the mold being provided with a main wall cavity offlowlimiting thinness, such cavity being interrupted by verticallydisposed channels of free-flowing depth throughout their entire extentand spaced from each other at intervals of not more than twice theflowing distance of metal through the main wall cavity, and a pouringsprue communicating with the lower ends of said channels.

2. A mold for casting a thin wall receptacle or like structure frommolten metal, the mold bein provided with a main wall cavity offlow-limitin thinness, such cavity being interrupted by verticallydisposed channels of free-flowing depth throughout their entire extentand spaced from each other at intervals of not more than about teninches, and a pouring sprue communicating with the lower ends of saidchannels.

3. A mold for casting from molten metal a receptacle or like structurehaving a main wall of not more than about A; inch thickness, the moldbeing provided with a main wall cavity of not more than about /3 inchthickness, such cavity being interrupted by vertically disposed channelsof free-flowing depth throughout their entire extent and spaced fromeach other at intervals of about not more than twice the flowingdistance of metal through the main wall cavity and a pouring spruecommunicating with the lower ends of said channels.

4. A mold for casting from molten metal a receptacle or like structurehaving a main wall of about A; inch thickness, the mold beingprovided'with a main wall cavity of about /8 inch thickness, such cavitybeing interrupted by vertically disposed channels about T g inch indepth, said channels being spaced from each other at intervals of notmore than about ten inches, and a pouring sprue communicating with thelower ends of said channel.

FRANK J. MORAVECKY.

